I have done a similar technique using ordinary spackle (which I think you could easily tint with food color or paint). You can make great embellishments using stencils, too. You must paint over or seal the spackle as it can be re-wetted and removed if it's not sealed somehow. Which might be a good thing if you want to remove it at some point. Here is a photo of a design I did, using a stencil, in my bathroom. It has been in the bathroom for over 14 years, with no compromise of the design.

It was just an ordinary 6" stencil with ivy design from AC Moore, or Michaels or Hobby Lobby. You wouldn't think the thinness of the stencil would have such a great raised effect, but it's just enough.

Here is step by step if you want to try this:

1. You just set the stencil in place (hold with your fingers, firmly, along the edges, or use painters tape to hold in place if you're doing a large stencil. Be sure to keep the stencil as flush with the wall as possible.
2. I used a dry foam brush to spread /dab the spackling. You want it to be like you're frosting a cake, just spread it over the whole stencil. A spackling tool works well, too.
3. When all of stencil is filled in with spackling, lift the stencil off right away, pulling from one end to the other.
4. Then rinse and dry stencil off for next section (so you don't get over lap of spackling from underneath on the wall around your next section).

Since I was doing a continuous ivy vine, I did one section, skipped a section, did the next one below, repeat. When the first sections were dry, I went in-between the unfinished area/section and filled in. It really dries relatively quickly (about 20 minutes?).

When all was completely dry I used acrylic paints to add the green to the leaves and vine detailing.

Be careful not to water down your paint too much (if at all), or the spackling will get mushy/wet, again. The nice thing about that, though, is, if you aren't happy with how it turns out/ or want to take it off, all you have to do is wet it, and wipe it off.

I used ordinary spackling for drywalling. Cheap and easy and a little goes a long way :)

Sorry for the long answer to your simple question :)